typenum 1.10.0

Typenum is a Rust library for type-level numbers evaluated at compile time. It currently supports bits, unsigned integers, and signed integers. It also provides a type-level array of type-level numbers, but its implementation is incomplete.

For a non-trivial example of its use, see one of the crates that depends on it. The full
list is here. Of note are
dimensioned which does compile-time type
checking for arbitrary unit systems and
generic-array which provides arrays whose
length you can generically refer to.